1, 5, 49, 1261, 62689, 7629469, 1294716361, 375074829229,

[Dean Hickerson]

ZAKIRS <zfseidov at ycariel.yosh.ac.il> wrote:

> suprisingly, this sequence's absent in OEIC:
>
> 1, 5, 49, 1261, 62689, 7629469, 1294716361, 375074829229,
>   135662633811769, 71859617272521901,
>
> before posting it to Neil, i dare ask you to find out
>
> what it can be (kind of puzzle?), thanks, zak

Brian L. Galebach replied:

> OK.  I can calculate the sequence now.  I still have no idea why I would
> want to calculate it however.  I suppose that's part of the question?  :-)

I agree.  Note that the similar but more natural sequence

1, 13, 361, 18589, 2293369, 392915461, 114454369129, 41578647715669,
22089188627685001, ...

is in the OEIS.

SPOILER:  To get ZAKIRS's sequence, add 1 before taking the numerator.

Dean Hickerson
dean at math.ucdavis.edu